A new study focusing on low-income women in St. Louis, MO concludes that expanding access to free contraception — just as the health care reform law does through its provision to provide birth control without a co-pay — leads to significantly lower rates of unintended teen pregnancy and abortion. Researchers found that when women weren’t prohibited by cost, they chose more effective, long-lasting forms of birth control and experienced many fewer unintended pregnancies as a result.

Researchers from the Washington University School of Medicine in St. Louis worked in partnership with the local Planned Parenthood affiliate to track over 9,200 low-income women in the St. Louis area, some of whom lacked insurance coverage, during a four-year Contraceptive CHOICE study. The CHOICE project simulated Obamacare’s birth control provision by allowing teens and women to select from the full range of FDA-approved contraceptive options and receive their preferred method at no cost. They found that birth rates among the teens who received free birth control in the CHOICE project were less than a fifth of the national teen birth rate — just 6.3 births per 1,000 teens, compared to 34.3 per 1,000 teens nationwide in 2010 — and abortion rates were less than half of both the regional and national rates.

And researchers are confident that these positive findings could extend to the rest of the nation, estimating that the national simulation of their CHOICE program could prevent one abortion for every 79 to 137 women given a choice between free birth control options. “As a society, we want to reduce unintended pregnancies and abortion rates. This study has demonstrated that having access to no-cost contraception helps us get to that goal,” Alina Salganicoff, director of women’s health policy at the Kaiser Family Foundation, told the Associated Press.In a press release, Planned Parenthood officials noted that the study strongly suggests that President Obama’s health reform law will help lower the abortion rate. “This study shows that the Affordable Care Act’s birth control benefit can dramatically reduce the need for abortion in the U.S. once it is fully implemented,” said Dana Singiser, the vice president of public policy and government relations for Planned Parenthood Federation of America. “To prevent unintended pregnancy, women need full information, full coverage and full choice for what type of birth control works best for them.”

Lowered rates of unintended pregnancy are directly related to increased access to contraception, and the CHOICE project reinforces the fact that increasing access involves removing cost barriers to birth control. Women of reproductive age currently spend about 68 percent more than men do on out-of-pocket health care costs, partly because of high contraception costs — for example, a year’s supply of oral birth control pills typically costs over $1,200 out of pocket. Nearly one in three U.S. women report they have stopped using their preferred contraceptive method, or used it less consistently and effectively, because they could not afford it.